This is a replacement rear output speed sensor tone wheel for GM transfer cases with a 49-spline mainshaft; NP261HD, NP263HD, NP261XHD and NP263XHD.
The speedometer in your vehicle receives signals created by the speed sensor’s magnetic pickup interacting with the peaks and valleys of the tone wheel to accurately indicate vehicle speed. If there is an issue in the speed sensing circuit it can cause the transmission to go into “limp” mode in an attempt to prevent additional damage.
Click here to view the RTV Silicone needed to seal the case halves when reassembling.
Which direction does the tone wheel face when installing it in the transfer case?
The tone wheel has a stepped edge on one side, be sure to position the wheel so that the stepped edge faces the transfer case pump.
Do I need to replace the speed sensor too?
If the tone wheel was damaged from making contact with the speed sensor both will need to be replaced. Carefully examine the speed sensor to verify if any contact has been made and if there has the sensor should be replaced.
What fluid should I use in the transfer case and how much is needed?
We recommend our Performance Transfer Case Fluid for use in ALL transfer cases and have seen improved performance over the factory recommended ATF or other alternate oil recommendations. Two-quarts are required to fill the NP261HD, NP263HD, NP261XHD and NP263XHD transfer cases.
I hear a grinding noise at low speed after reassembling the transfer case. What could that be?
A low speed grinding noise is most commonly caused by the rear output bearing snap ring not being fully seated causing the bearing to move out of proper alignment. Verify that the snap ring is fully engaged and properly seated in the rear housing and the locating groove in the bearing.
What would cause a speed sensor correlation code after reassembling the transfer case?
A speed sensor correlation code is often accompanied by a low speed grinding noise and is frequently caused by the rear output bearing snap ring not being fully seated causing the bearing to move out of proper alignment. Verify that the snap ring it fully engaged and properly seated in the rear housing and the locating groove in the bearing.